1请编写C++代码实现一个队列类Queue要求具有以下方法：void enqueueint val将一个元素添加到队列的尾部。int dequeue ：删除队列的头部元素并返回该元素的值。bool isEmpty：判断队列是否为空。boolisFull：判断队列是否已满。

class Queue { private: int* arr; int front; int rear; int capacity; public: Queue(int size) { arr = new int[size]; capacity = size; front = 0; rear = -1; } ~Queue() { delete[] arr; } void enqueue(int val) { if(isFull()) { cout << "Queue is full." << endl; return; } rear++; arr[rear] = val; } int dequeue() { if(isEmpty()) { cout << "Queue is empty." << endl; return -1; } int val = arr[front]; front++; return val; } bool isEmpty() { return (rear < front); } bool isFull() { return (rear == capacity - 1); } }